Bacillus anthracis, the virulent, endospore-forming bacterium notorious for its recent use as a bioterror weapon, has plagued humans and livestock from antiquity (Friedlander 2000). The bacterium was associated with the founding of the sciences of bacteriology and immunology, highlighted by Pasteur's famous demonstration of vaccine protection of sheep at Pouilly-le-Fort, France. Since then, the attention Bacillus anthracis has received has largely revolved around its properties that make it ideally suited as a biological weapon as it forms heat resistant spores that are easy to produce and to transport, and can infect via the aerosol route.